pin migration, part 1

lib/core/auth_service.dart

@@ -39,13 +39,13 @@ class AuthService with Store {
 
   Future<void> setPassword(String password) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
-    final encodedPassword = encodedPinCode(pin: password);
+    final hashedPassword = await argon2Hash(password: password);
     // secure storage has a weird bug on macOS, where overwriting a key doesn't work, unless
     // we delete what's there first:
     if (Platform.isMacOS) {
       await secureStorage.delete(key: key);
     }
-    await secureStorage.write(key: key, value: encodedPassword);
+    await secureStorage.write(key: key, value: hashedPassword);
   }
 
   Future<bool> canAuthenticate() async {
@@ -64,10 +64,8 @@ class AuthService with Store {
 
   Future<bool> authenticate(String pin) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
-    final encodedPin = await secureStorage.read(key: key);
-    final decodedPin = decodedPinCode(pin: encodedPin!);
-
-    return decodedPin == pin;
+    final hashedPassword = await secureStorage.read(key: key);
+    return verifyArgon2Hash(password: pin, hash: hashedPassword!);
   }
 
   void saveLastAuthTime() {

lib/core/backup_service.dart

@@ -445,7 +445,7 @@ class BackupService {
     });
 
     await _flutterSecureStorage.delete(key: pinCodeKey);
-    await _flutterSecureStorage.write(key: pinCodeKey, value: encodedPinCode(pin: decodedPin));
+    await _flutterSecureStorage.write(key: pinCodeKey, value: (await argon2Hash(password: decodedPin)));
 
     keychainDumpFile.deleteSync();
   }
@@ -473,7 +473,7 @@ class BackupService {
     });
 
     await _flutterSecureStorage.delete(key: pinCodeKey);
-    await _flutterSecureStorage.write(key: pinCodeKey, value: encodedPinCode(pin: decodedPin));
+    await _flutterSecureStorage.write(key: pinCodeKey, value: (await argon2Hash(password: decodedPin)));
 
     keychainDumpFile.deleteSync();
   }

lib/entities/default_settings_migration.dart

@@ -1,5 +1,6 @@
 import 'dart:io' show Directory, File, Platform;
 import 'package:cake_wallet/bitcoin/bitcoin.dart';
+import 'package:cake_wallet/entities/encrypt.dart';
 import 'package:cake_wallet/entities/exchange_api_mode.dart';
 import 'package:cw_core/pathForWallet.dart';
 import 'package:cake_wallet/entities/secret_store_key.dart';
@@ -187,6 +188,7 @@ Future<void> defaultSettingsMigration(
           break;
         case 26:
           await pinEncryptionMigration(secureStorage: secureStorage);
+          break;
         default:
           break;
       }
@@ -384,24 +386,32 @@ Future<void> pinEncryptionMigration({required FlutterSecureStorage secureStorage
   try {
     // first, get the encoded pin:
     final keyForPinCode = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
-    String? encodedPin;
-    encodedPin = await secureStorage.read(key: keyForPinCode);
+    String? encodedPin = await secureStorage.read(key: keyForPinCode);
 
-    // if (encodedPin == null) {
-    //   return;
-    // }
+    // we don't have a pin?!?
+    if (encodedPin == null) {
+      print("pinEncryptionMigration: no pin found in secure storage!");
+      // this should never happen, but just in case let's just set the pin to "0000"
+      // as it's better than permanently locking the user out with an un-decryptable pin
+      encodedPin = encodedPinCode(pin: "0000");
+    }
 
-    // // ensure we overwrite by deleting the old key first:
-    // await secureStorage.delete(key: keyForPinCode);
-    // await secureStorage.write(
-    //   key: keyForPinCode,
-    //   value: encodedPin,
-    //   iOptions: IOSOptions(accessibility: KeychainAccessibility.first_unlock),
-    //   mOptions: MacOsOptions(accessibility: KeychainAccessibility.first_unlock),
-    // );
+    // decode & re-encode the pin:
+    final decodedPin = decodedPinCode(pin: encodedPin);
+    final hashedPin = await argon2Hash(password: decodedPin);
+
+    // ensure we overwrite by deleting the old key first:
+    await secureStorage.delete(key: keyForPinCode);
+    // write the new argon2 hashed pin:
+    await secureStorage.write(
+      key: keyForPinCode,
+      value: hashedPin,
+      iOptions: IOSOptions(accessibility: KeychainAccessibility.first_unlock),
+      mOptions: MacOsOptions(accessibility: KeychainAccessibility.first_unlock),
+    );
   } catch (e) {
     // failure isn't really an option since we'll be updating how pins are stored and used
-    print(e);
+    print("pinEncryptionMigration: $e");
   }
 }
 

lib/entities/encrypt.dart

@@ -1,13 +1,25 @@
 import 'package:encrypt/encrypt.dart';
 // import 'package:password/password.dart';
 import 'package:cake_wallet/.secrets.g.dart' as secrets;
+import 'package:dargon2_flutter/dargon2_flutter.dart';
+
+Future<String> argon2Hash({required String password}) async {
+  final result = await argon2.hashPasswordString(password, salt: Salt.newSalt());
+  // the salt is stored within the encoded string:
+  return result.encodedString;
+}
+
+Future<bool> verifyArgon2Hash({required String password, required String hash}) async {
+  return argon2.verifyHashString(password, hash);
+}
+
+// @@@@@@@@@@@@@@@ OLD (kept for reference purposes, do not use!) @@@@@@@@@@@@@
 
 String encrypt({required String source, required String key}) {
   final _key = Key.fromUtf8(key);
   final iv = IV.allZerosOfLength(16);
   final encrypter = Encrypter(AES(_key));
   final encrypted = encrypter.encrypt(source, iv: iv);
-
   return encrypted.base64;
 }
 
@@ -16,7 +28,6 @@ String decrypt({required String source, required String key}) {
   final iv = IV.allZerosOfLength(16);
   final encrypter = Encrypter(AES(_key));
   final decrypted = encrypter.decrypt64(source, iv: iv);
-
   return decrypted;
 }
 
@@ -31,26 +42,22 @@ String hash({required String source}) {
 
 String encodedPinCode({required String pin}) {
   final source = '${secrets.salt}$pin';
-
   return encrypt(source: source, key: secrets.key);
 }
 
 String decodedPinCode({required String pin}) {
   final decrypted = decrypt(source: pin, key: secrets.key);
-
   return decrypted.substring(secrets.key.length, decrypted.length);
 }
 
 String encodeWalletPassword({required String password}) {
   final source = password;
   final _key = secrets.shortKey + secrets.walletSalt;
-
   return encrypt(source: source, key: _key);
 }
 
 String decodeWalletPassword({required String password}) {
   final source = password;
   final _key = secrets.shortKey + secrets.walletSalt;
-
   return decrypt(source: source, key: _key);
 }

lib/main.dart

@@ -163,7 +163,7 @@ Future<void> initializeAppConfigs() async {
       transactionDescriptions: transactionDescriptions,
       secureStorage: secureStorage,
       anonpayInvoiceInfo: anonpayInvoiceInfo,
-      initialMigrationVersion: 25);
+      initialMigrationVersion: 26);
 }
 
 Future<void> initialSetup(